ByNicholas Riccardi, Associated PressJuly 18, 2014

In this April 17, 2014 file photo, plaintiffs challenging Oklahoma's gay marriage ban Sharon Baldwin, left, and her partner Mary Bishop leave court following a hearing at the 10th U.S. Circuit Court of Appeals in Denver, Colo.

Denver — A federal appeals court ruled Friday that Oklahoma must allow gay couples to wed, marking the second time it has found the US Constitution protects same-sex marriage.

The decision from the 10th US Circuit Court of Appeals upholds a ruling that struck down Oklahoma's gay marriage ban. But the Denver-based court immediately put its decision on hold pending an appeal, meaning same-sex couple won't be allowed to marry in Oklahoma for now.

The 2-1 ruling comes after the same three-judge panel ruled in June that Utah's ban on same-sex marriage violates the Constitution. It was the first time an appellate court determined that last year's US Supreme Court decision striking down the Defense of Marriage Act meant states couldn't deny gays the ability to wed. That ruling also is on hold, and Utah's attorney general has said he plans to appeal to the US Supreme Court.

The lawsuit challenging Oklahoma's ban was filed against the Tulsa County clerk, whose attorneys were still considering their options Friday afternoon. But they noted the panel's dissenting judge argued that changing the definition of marriage should belong to Oklahoma residents, not a federal court.

"Every child deserves a mom and a dad, and the people of Oklahoma confirmed that at the ballot box when they approved a constitutional amendment that affirmed marriage as a man-woman union," said Byron Babione, senior attorney for Alliance Defending Freedom, which is defending the county clerk.

Proponents of gay marriage quickly planned rallies Friday in Oklahoma City and Tulsa to celebrate the ruling.

"We're excited that Oklahoma will be counted among the places where all of its citizens are treated equally," said Toby Jenkins, executive director of Oklahomans for Equality.

In its 46-page ruling Friday, the judges dealt less with the constitutionality of same-sex marriages and instead focused more on arcane legal matters of whether the Oklahoma couples sued the correct government officials.

However, Justice Carlos Lucero reiterated that the court has already found that same-sex couples have a fundamental right to marry that cannot be breached by the state's concern with keeping the focus of marriage on the procreative potential of man-woman unions. He wrote that Oklahoma's ban, "denies a fundamental right to all same-sex couples who seek to marry or to have their marriages recognized regardless of their child-rearing ambitions."

Justice Jerome A. Holmes concurred but stressed in his own opinion that the court did not find that voters exhibited legal animus, or dislike, toward gay individuals when they outlawed same-sex marriage in 2004. Justice Paul Kelly Jr. dissented.

The two decisions give increased momentum to a legal cause that has compiled an impressive string of lower court victories. More than 20 courts have issued rulings siding with gay marriage advocates since the Supreme Court's DOMA ruling in June 2013. The rulings have come in 17 states, with Florida being the latest.

Two of the most striking of those decisions were in conservative Utah and Oklahoma, which saw their voter-approved gay marriage bans struck down in December and January, respectively. In Utah, more than 1,000 same-sex couples married before the Supreme Court issued a stay.

It's unclear whether the two cases will be the first to reach the Supreme Court. The high court could choose from cases moving through five other federal appellate courts, and it won't consider a case until next year at the earliest.

Attorneys representing Utah and Oklahoma argued voters have the right to define marriage in their states, and unions between a man and woman are best for children.

Gay rights lawyers countered that voters cannot define marriage in a way that deprives gay people of their fundamental rights, and say there is no proof that gay couples make inferior parents.

Ten years ago, nearly a dozen states outlawed gay marriage. Now same-sex marriage is legal in 19 states and the District of Columbia, and recent polls show a majority of Americans support it.